Conrad Gesner (March 26, 1516 - December 13, 1565) was a Swiss botanist and zoologist. Gesner's Historiae Animalium (Studies on Animals) is considered to be the first modern zoological work. This first attempt to describe many of the animals accurately is illustrated with hand-colored woodcuts drawn from personal observations by Gesner and his colleagues. He died of the plague, at the age of 49, the year after his ennoblement.